(19)
(11) EP 0 889 615 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
18.04.2001 Bulletin 2001/16

(43) Date of publication A2:
07.01.1999 Bulletin 1999/01

(21) Application number: 98112040.5

(22) Date of filing: 30.06.1998
(51) International Patent Classification (IPC)7: H04L 5/14, H04L 27/26
(84) Designated Contracting States:
AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE
Designated Extension States:
AL LT LV MK RO SI

(30) Priority: 30.06.1997 US 884895

(71) Applicant: Integrated Telecom Express
Santa Clara, California 95051 (US)

(72) Inventors:
  • Liu, Young Way
    La Mirada, California 90638 (US)
  • Liu, Ming-Kang
    Cupertino, California 95014 (US)
  • Chen, Steve
    San Jose, California 95132 (US)

(74) Representative: Lins, Edgar, Dipl.-Phys. Dr.jur. 
Gramm, Lins & Partner GbR, Theodor-Heuss-Strasse 1
38122 Braunschweig
38122 Braunschweig (DE)

   


(54) Multicarrier transmission with variable data rate


(57) A high speed communications system is provided which uses a selectable, desirable portion of the total available bandwidth of a transmission channel. In a preferred embodiment, the invention is an ADSL compatible modem which selects a sub-set of the available downstream DMT sub-channels based on an evaluation of such sub-channels by appropriate signal processing circuitry. An analog front end (AFE) contains sub-band filtering causes an upstream transceiver to use only this selected number of available sub-channels for downstream data transmission. This reduces hardware costs and complexity while still preserving compatibility with applicable ADSL standards and providing a high speed data link. The target data rate of the modem can be further enhanced to the point of achieving full protocol capability by increasing or upgrading the AFEs, and/or the signal processing circuitry in order to increase the number of processable transmitted downstream sub-channels.






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